In the state of the art, such as of DE 603 13 240 T2, a fuel-injection device is known for feeding pressurized fuel to a fuel injector, whereby the fuel-injection system contains the fuel injector and comprises the following: a pressure storage volume in order to feed fuel at an initial injection pressure level through a fuel feed duct to a fuel injector, a pumping agent to increase the pressure of the fuel fed to the injector to a second injection pressure level, whereby the pumping agent comprises a defined pump chamber inside a plunger bore and a plunger piston which can move inside the plunger bore so as to apply pressure to the fuel in the pump chamber. It is emphasised as being significant that there is still a valve element positioned in the fuel feed duct between the pump chamber the pressure storage volume, the valve element being capable of being switched between a first position, in which i) fuel at the first injection pressure level (P1) is fed to the injector and ii) the pump chamber is connected to the pressure storage volume so that at the first injection pressure level (P1) fuel can flow from the pressure storage volume into the pump chamber, and a second position in which the connection between the injector and the pressure storage volume is interrupted so that at the second injection pressure level (P2) fuel is fed to the injector, whereby the pumping agent continues to comprise a drive element which can be operated together with the plunger piston, whereby the drive unit is connected to a rocker arm of the machine in such a way that a movement of the drive unit causes a pivot movement of the rocker arm.
Fuel injection valves are also known from DE 60 2005 001 261 T2. Here a fuel-injection device for a combustion engine is presented, whereby the fuel-injection device also presents a coupling agent to couple the movement of an outer valve and that of an inner valve in cells in which the outer valve is moved away from the outer valve seat by an amount exceeding a predefined cell magnitude, which has the effect of causing the inner valve to be lifted away from an inner valve seat to create a third injection state in which a fuel feed is enabled equally by first and second nozzle outlets.
Methods for producing metal components are familiar from DE 10 2009 028 105 A1. Here, a generative method for producing a metal component is presented comprising the following stages: a) scanning of at least one 3D-CAD data set containing the geometry and material distribution of the component to be produced, b) selection of at least one metallic main body, c) configuration and/or removal of a local geometry on the metallic main body by means of an additive process and d) if necessary fine machining, in particular high-precision machining by means of a removal process, as well as a device for the execution of the method and a metal component in which the materials of the metallic main body and of the local geometry differ.
A fuel-injection valve is also known from DE 10 2004 015 746 T2, for example. Here a fuel-injection valve of a combustion engine is presented comprising a nozzle unit in which an outer nozzle needle interacting with at least a first injection opening and an inner nozzle needle with at least a second injection opening, the inner nozzle needle being positioned so as be able to move through the outer nozzle needle axially, and with a valve control unit which controls a fluid pressure that exists in a valve control chamber and whose level determines the position of the outer and inner nozzle needle. A pressure chamber is provided whose volume can be altered by the movement of at least one of the two nozzle needles in such a way that the pressure chamber undergoes a change in pressure and an additional force acts on at least one of the nozzle needles.
Further state of the art is familiar from DE 100 46 304 C1, DE 196 33 260 A1, DE 10 2005 049 534 A1, EP 2 018 925 A2 and DE 198 54 793.
Generic fuel-injection metering devices are familiar from diesel injection systems and from petrol injection systems, so-called “GDI systems”. Such GDI systems, that is to say Gas Direct Injection systems, have to be able to handle pressures of up to 500 bar, i.e. 50 MPa. For this reason, the components of the injection system have to be adapted to the pressure load. Here it is crucial for the components produced to demonstrate good surface quality so as to reduce or ideally eliminate the risk of breakage due to stress concentration.
For this purpose lengthwise grooves, which can also be referred to as pockets, are provided in the main body, normally extending outwards radially from a main hole. Frequently five pockets are required.
Normally the main bodies of the fuel-injection metering devices are revolved inside and outside. On the inside, i.e. further defining the inner face of the main body, a milling process or other machining process is applied to create the longitudinal grooves or pockets. However, this requires lengthy processing, causes burr formation and increases costs. The burr formation also results in a poorer surface quality. This means that the parts to be produced per unit of time are more expensive, of poorer quality and limited in use.
The attempt was therefore made to create a suitable main body using other methods. As a more recent option, an MIM method is used, i.e. a metal injection moulding method. A specific configuration that lends itself here is powder injection moulding or similar injection moulding methods. Unfortunately, however, the main bodies are also subject to considerable risk of breakage in this case since the material is more brittle. The component surface can also be porous, which is likewise undesirable.
More extensive use of cold-forming methods has also been tested, whereby such processes essentially produce good results but the concentricity and position of the inner recesses and pockets is currently too imprecise, in particular in relation to the outer circumference. The inner engraving, i.e. the inner recesses or space organization of the inner recesses, is then eccentric.
However, workpiece precision is a vital property and crucial if the component is to be durable and function precisely. This is very important in terms of the reproducibility of the injection pattern from one component to another. Such reproducibility is very much desired.